She began her career challenging the Boy Scouts of America to admit a girl for the first time and won. She has challenged all-male clubs, fought for gay rights and been voted America's "most effective lawyer".

Now Gloria Allred, the advocate representing one of Tiger Woods's alleged lovers, Rachel Uchitel, and another unnamed mistress, is back again in front of the cameras where she likes to be. A prospect not likely to bring the disgraced golfer any comfort.

Allred's appearance in the Woods saga has set up a new dynamic in an already febrile story, pitting, as it does, the world's most successful sportsman against one of America's most aggressive, successful and media-savvy "sharks".

Among her critics, Arianna Huffington has described Allred as the "most disturbing symbol" of what has gone wrong with the US legal system. But Allred's own self-image is of a feminist, campaigning lawyer – champion of the weak against the strong.

If one thing is certain, it is that Allred has a taste for the trappings of celebrity. She lives in a $5m beachfront house in Malibu, California. She appears on television, both as a commentator and representing her high-profile cases almost as often as Woods himself.

Indeed, she has become such a fixture in the public imagination that she has been lampooned on the TheSimpsons, South Park and Family Guy – something even Woods has not achieved. In interviews, Allred has not denied her celebrity status. However, she has insisted that the other aspects of her career be properly recognised. "In a way we are almost like the court of last resort for many cases," she once said. "We take cases that some people think are impossible to win. We win them. We win multi-million dollar verdicts."

Yet, having been recognised by presidents Reagan and Clinton for her advocacy – particularly over equality issues – more recently Allred has become as well-known for having represented a series of people best described as prime tabloid-fodder, including acting against Michael Jackson when he hung his child out of a window, and conducting a feud with Nadya Suleman, the octuplets' mother. She won the day for Hunter Tylo, the Melrose Place soap opera actress fired for becoming pregnant, and acted for the family of Nicole Brown, OJ Simpson's murdered wife.

She demonstrated her taste for the limelight during the trial of the murderer Scott Peterson when she represented his former mistress and star witness Amber Frey during his trial for the killing of his wife Laci and their unborn child. A gagging order imposed on those involved in the case did not extend to Allred and she was frequently on television news programmes giving her view of the proceedings while keeping the details of Frey's past from public view.

Allred's view of the law – expounded on her website for potential clients – combines an American view of universal entitlement with both grandiose and folksy trappings. "To victims of domestic violence, I say, think of yourself as strong, not weak. Remember the words of Eleanor Roosevelt, 'Women are like teabags – they never know how strong they are until they get into hot water'.

"Remember that the denial of civil rights is not a small thing. The Holocaust began when the Jewish people in Germany initially were deprived of their civil liberties. It escalated into them being deprived of their lives. We must take a stand wherever and whenever someone is denied a basic civil right.

"As I say in the conclusion of my book: "More than anything, in the face of adversity and injustice, I want you to overcome your fear and be fearless, find your voice and not be voiceless, exert your power and not be powerless. I want you to be able to fight back and win justice for yourself, your children, your family, and your community."

But it was one of her appearances on TV – commenting on high-profile cases as the stories break – that earned her one of her harshest rebukes – from former basketball star Charles Barkley. He said to her face on CNN: "Every time some high-profile case breaks out, you jump on television and act like you're God! Only God can judge other people. Why don't you go back to your office, wait on another case, and shut the hell up?"

Already, Allred appears to have rattled Woods. She is reported to have negotiated a substantial pay-off for Uchitel against the threat of "making a statement about Ms Uchitel's relationship with Tiger Woods" at an embarrassing press conference, promptly cancelled after the deal was done.

It has not only been the threat of what Uchitel might say that Allred has dangled over the golfer. In recent days she has also suggested that she has other weapons in her armoury against him, saying: "I do represent other clients in reference to Tiger Woods," adding, however, that "we will not confirm or deny the names of our clients."

In that respect she appears to be confirming the biggest charge of her critics – that she prefers to try her adversaries in the court of public opinion as much as in the courts themselves, using the media as effectively as she does the law.